Electric heating fan

ABSTRACT

The invention is directed to a heating fan ( 100 ) with an inner space ( 110 ) in which is arranged an air channel ( 810 ) which is partially made of plastic. An electric heating body ( 300 ) is arranged behind a fan ( 800 ) in an air flow direction ( 821 ). According to the invention, this fan is constructed such that a fan wheel ( 801 ) of a radial fan, which fan wheel ( 801 ) is contained in the fan ( 800 ), has two suction sides ( 805, 806 ) which are separated by a dividing wall ( 804 ). During operation, a first air flow ( 822 ) is sucked in from outside ( 1 ) through the first suction side ( 805 ) which is open to a first air inlet opening ( 221 ). The second suction side ( 806 ) is arranged in a fan space ( 111 ) of the heating fan ( 100 ) and is pneumatically connected to second air inlet openings ( 222 ). The fan is arranged in front of a ceramic heating element ( 301 ) of the electric heating body ( 300 ) so that the first air flow ( 822 ) and the second air flow ( 823 ) stream through the heating body ( 300 ).

RELATED APPLICATIONS

The present application claims priority to German Application No.102016005552.9 filed on May 9, 2016, the entirety of which isincorporated herein by reference.

FIELD OF THE INVENTION

The invention is directed to a heating fan with an inner space in whichis arranged an air channel which is at least partially made of plastic.An electric heating body is arranged behind a fan in an air flowdirection.

BACKGROUND

Heating fans in which an electric heating body is arranged in an airchannel are known commercially. A fan generates an air flow which isblown through the heating body and heated in the heating body. PTCheating bodies are advantageously used in devices which are at leastpartially made of plastic. For physical reasons, these PTC heatingbodies are subject to thermal self-regulation, i.e., they do notoverheat in the absence of air flow so that the heating body thermallyself-adjusts to a safety temperature.

A heating fan which has a heating body with PTC heating elements whichis used in the exhaust air flow of a blower is known from DE 9313789.3.The blower has a blower wheel and is configured as a radial blower. Thesuction of blower air takes place horizontally via inlet air orifices inthe rear side and/or side walls of the heating fan housing with axialin-flow into the blower wheel. The heating fan further has a controller,and the heating register is divided into zones which are formedvertically adjacent to one another so that heating outputs of differentmagnitudes are possible. Further, an air filter is arranged in the inletair orifices.

SUMMARY

It is the object of the invention to reduce heating of the plastic partsin correct operation and incorrect operation and to allow a flatconstruction of the heating fan.

This object is met through the features of claim 1.

The fan has a fan wheel of a radial fan with a first suction side and asecond suction side which are separated by a dividing wall. The firstsuction side is open to a first air inlet opening through which a firstair flow is sucked in from the outside through the first suction sideduring operation. The second suction side is arranged toward a fan spaceof the heating fan, and the second suction side is pneumaticallyconnected to second air inlet openings. Further, the fan isadvantageously arranged in front of a ceramic heating element of theelectric heating body so that the first air flow and the second air flowstream through the heating body.

A guide wall through which the fan space is formed is advantageouslyarranged in the inner space. Accordingly, at least some of the secondair flow is guided to the second suction side.

In a preferred configuration, the fan space is situated between thesecond suction side and the second air inlet opening. During operationof the heating device, air flows out of an inner space into the secondsuction side.

According to a further aspect of the invention, the fan has an exhaustopening through which a total air flow is guided to the heating bodyduring operation of the heating fan. Further, the heating body isarranged behind the exhaust side in air flow direction.

The second air inlet opening is preferably arranged in the rear wall.

In particular, the first air inlet opening has a larger opening areathan the second air inlet opening. The first air inlet openingpreferably makes up approximately 55% to 90% of the total opening areaof the first and second air inlet openings. Further, the mass flow ofthe first air flow is greater than the mass flow of the second air flowduring operation of the heating fan. The mass flow through the firstopening amounts in particular to approximately 60% to 80% of the totalmass flow.

In an embodiment example, the fan wheel of the fan has first bladeswhich are arranged toward the first suction side. Further, it has secondblades of the fan which are arranged toward the second suction side.

According to the invention, the first blades and the second blades ofthe fan wheel are separated by a dividing wall.

Finally, it is advantageous that the first blades are larger than thesecond blades, in particular at least 30% to 70% larger, particularlyapproximately 50% larger.

A flat construction can advantageously be realized in which the airsuction preferably takes place from the rear through a rear wall whichis preferably further provided to be connected to a mounting wall.Accordingly, the suction is carried out through the rear wall via aradial blower in which the air flow is deflected by 90°. According tothe invention, two air flows are supplied to the radial blower axiallyfrom two sides.

The dividing wall is advantageously provided for separating the two airflows. First blades are arranged on one side of the dividing wall, whichfirst blades are preferably larger than second blades on the other sideof the dividing wall. The dividing wall is preferably cup-shaped towardthe first suction side, a fan motor, particularly with a needle, beingarranged in the area of the cup-shaped dividing wall.

Further, the fan motor lies so far inside the fan that it is so-to-speakin the cup, i.e., preferably in the dividing wall, and is surrounded bythe first blades. Two suction areas are formed in this way. A more orless direct region through the first air inlet opening and a secondregion through the second air inlet opening, wherein the air flowthrough the second air inlet openings is initially sucked through theinner space of the heating fan, and the exhaust heat occurring there, inparticular of the heating body, is sucked out through the second airflow.

The inner space of the heating fan, particularly the area between thefront and an air channel, is vented through the second air inletopenings even when the heating fan is stationary. Accordingly, theafter-heat given off by the heating body is given to a convection flowof air which can stream through the second air inlet openings throughthe device, particularly from bottom to top. The second air inletopenings serve as inlet openings for the second air flow duringoperation of the heating fan when the fan motor drives the fan.

Advantageously, the air channel is made of plastic at least partially orin its entirety.

When the device is stationary, a portion of the second air inletopenings advantageously serves as inlet opening for cooling air andanother portion of the second air inlet openings serves as outletopening for the convection air flowing through the device. In stationarystate, cool air accordingly flows through the second air inlet openingsarranged below in the rear wall in the area of the air outlet into thedevice. The convection air which is at least slightly heated flows outof the heating fan again in the stationary state through the second airinlet openings which are preferably arranged above the fan in the rearwall of the device.

A controller is spatially separated from the fan by a guide wall.Accordingly, the second air flow is divided into two partial flows, afirst partial flow of the second air flow streams past the controller,while a larger, second partial flow of the second air flow flows fromthe second air inlet openings to the fan. Accordingly, the controller isslightly cooled by a small partial flow so that, in a way, roomtemperature or air at room temperature flows against it during operationof the heating device.

When the heating device is stationary, an air flow of room air alsoflows through the second air inlet openings, preferably in the area ofthe rear wall below in the air outlet grating through the rear wall intothe device and flows through the guide wall separately to thecontroller. Accordingly, the controller is continuously supplied withroom air during operation of the heating device and also when the fan isstationary.

Further, at least one or two safety temperature limiters areadvantageously provided on the heating body or in the area of theheating body. These safety temperature limiters are outfitted asbang-bang controllers or on-off controllers and/or also advantageouslyas fuses.

It is particularly advantageous and reliable to form two safetytemperature limiters at the PTC heating body, for one, with an on-offcontroller with a first safety switching temperature and with a fusewith a second safety temperature, where the switching temperature of theon-off controller is advantageously lower than the second safetytemperature of the fuse. This causes the heating body to be switched offin case of failure initially of the on-off controller so that a safercondition of the heating fan is achieved. If the on-off controllerfailed, the heating body would heat the device again and the fuse wouldblow to prevent overheating.

A fore-grating with air baffles is advantageously provided in the airchannel for guiding the air. In this way, the air flow which has formedbehind the heating body is deflected a first time. The baffles orguiding devices are preferably arranged substantially horizontally. Theair outlet grating which has directed a portion of the air outletopenings toward the bottom and another portion forward in the directionof the front is advantageously arranged behind the first air guidinggrating. The guiding surfaces or baffles of the first air guidinggrating and air outlet grating are advantageously arranged at an angleto one another to prevent sprayed water from entering.

The heating fan is advantageously outfitted with a device for fasteningto a mounting wall. At least the first air flow is advantageously suckedinto the heating fan during operation of the fan between the mountingwall, not shown, and the rear wall. The rear wall is accordinglyarranged at the mounting wall with the wall fastening, not shown, andtherefore also the entire heating fan.

The fan advantageously has a fan wheel of a radial blower,advantageously with a first suction side and a second suction side whichare separated by a dividing wall.

According to a further idea, the controller is substantially separatedfrom the fan space by the guide wall.

The common air flow which is conveyed through an air outlet by theblower and which is formed by the first air flow and second air flow isadvantageously heated by a ceramic PTC heating element.

BRIEF DESCRIPTION OF DRAWINGS

To the accomplishment of the foregoing and related ends, certainillustrative embodiments of the invention are described herein inconnection with the following description and the annexed drawings.These embodiments are indicative, however, of but a few of the variousways in which the principles of the invention may be employed and thepresent invention is intended to include all such aspects and theirequivalents. Other advantages, embodiments and novel features of theinvention may become apparent from the following description of theinvention when considered in conjunction with the drawings. Thefollowing description, given by way of example, but not intended tolimit the invention solely to the specific embodiments described, maybest be understood in conjunction with the accompanying drawings, inwhich:

FIG. 1 shows the heating fan in section;

FIG. 2 shows the heating fan 100 in a sectional three-dimensional view;

FIG. 3 shows a section viewed toward the inner guide wall;

FIG. 4 shows the heating fan with its rear wall and the component partslocated in the inner space;

FIG. 5 shows the heating device from the front without its front;

FIG. 6 shows the controller arranged on the inner side.

DETAILED DESCRIPTION

FIG. 1 shows a heating fan 100 arranged in a space 1. An inner space 110in which an air channel 810 is arranged is located in the heating fan100. In the embodiment example, the air channel 810 is made of plasticand is configured to guide a hot air flow 820. During operation of theheating fan 100, air is guided in an air flow direction 821 through theheating fan 100 or in air flow direction 821 through the air channel810. Air flow direction 821 comes about through the operation of a fan800 which is arranged in front of or in the air channel 810.

The fan 800 has a fan wheel 801 which is driven by a fan motor 830. Thefan motor 830 has a hub 831. The fan wheel 801 has two regions. Firstblades 808 are arranged in the fan wheel in one region and second blades809 are arranged on another side in another region. The first blades 808and second blades 809 are separated by a dividing wall 804 of the fan800.

Accordingly, operation of the heating fan produces a first air flow 822which is sucked into the heating fan 100 through first air inletopenings 221. The first air flow 822 is generated by the first blades808 during operation of the fan 800 on the first suction side 805. Inthe embodiment example, an air filter 860 is advantageously arranged onthe first suction side.

A second air flow 823 is generated by the second blades 809 duringoperation of the fan 800. The second blades 809 which are located on asecond suction side 806 suck air from a fan space 111. In the embodimentexample, the fan space 111 is located between a front 210 and the secondsuction side 806 or the second blades 809 of the fan 800. The second airflow 823 is sucked in through second air inlet openings 222 which arearranged in the lower area of a rear wall 220 and in the upper areaabove a wall spacer 270 in the embodiment example.

A further spacer 270 is arranged below in the heating fan 100 in therear wall 220 at the level of the air exhaust grating 813 only justtoward the rear wall 220. Accordingly, the fan 800 conveys two airvolume flows, namely, first air volume flow 822 and second air volumeflow 823, during operation, i.e., when the fan motor 830 is suppliedwith current.

The first air volume flow 822 and the second air volume flow 823 make atotal air flow 824 in air flow direction 821 just inside or downstreamof the fan 800. This total air flow 824 results at least upstream of aheating block 300 which the total air flow 824 passes during operationof the heating fan 100. Accordingly, the heating block 300 is arrangeddownstream of the fan 800 viewed in air flow direction 821 and has anelectric heating element which is a ceramic heating element 301 in theembodiment example. Therefore, a total air volume flow 824 is generatedby the fan 800 and conveyed to the heating block 300 at an exhaust side807. As is shown in FIG. 1, the fan 800 accordingly sucks a first airflow 822 through a first air outlet opening 221 and a second air flow823 through second air inlet openings 222 via a fan space 111. The twoair flows 822, 823 are then heated by the heating block 300 as total airflow 824 and given off through the air exhaust grating 813 in space 1.In an advantageous manner, the hot air flow 820 is given off obliquelydownward into space 1.

Arranged in the air channel 801 upstream of the air exhaust grating 813is an air deflector 816 which is formed by a plurality of baffles 817arranged horizontally in the embodiment example. In the embodimentexample according to FIG. 1, the air deflector 816 comprises baffles 817which are made of plastic and which also have an angle 818 ofapproximately 110°.

According to FIG. 2, the heating fan 100 is shown with a suction grating812 which is arranged toward the first blades 808 in air flow direction821 during operation of the fan 800. The air suction grating 812 islocated on the first suction side 805.

An air filter holder 861 is advantageously provided in the embodimentexample. A lint filter, not shown, or a filter is inserted therein.Accordingly, the first air flow 822 which is generated by the firstblades 808 is cleaned through filters and/or guided through an airsuction grating 812.

Further, in the embodiment example the heating fan 100 has a cable space290 in which a connection cable, not shown, can be wound up or stowed.Accordingly, the cable space 290 is located in the area of the airchannel 810. The cable is advantageously connected to a socket terminalstrip 710.

Further, the heating fan 100 has an operator control part 401 with whicha controller 400 can be adjusted. A target temperature for space 1 canbe set with the controller 400. In an advantageous manner and forprecise control, air is supplied to the controller 400 which is arrangedin the inner space 110, which takes place through the second air inletopenings 222 in the embodiment example. During operation of the device,air is sucked in through all second air inlet openings 222, flows pastthe controller 400 at least partially and provides the controller 400with air from space 1. When the heating fan 100 is stationary, thecontroller 400 is ventilated with air from space 1 through the secondair inlet openings 222 which are situated below and which are arrangedin the area of cable space 290. The air flows through convection fromthe bottom, i.e., the second air inlet openings 222 arranged in the areaof the cable 290, to the controller where it passes out of the deviceagain in the vicinity of the controller 400 through the second air inletopenings 222 arranged at the top.

Therefore, the function of the second air inlet openings 222 changeswhen the heating fan 100 is stationary. In this case, air flows out ofthe heating fan 100, whereas during operation of the heating fan 100 itflows through the second air inlet openings 222 arranged at the top ofthe controller 400 into the device toward the second suction side 806.

Further, a guide wall 112 is arranged at the air channel 810 for atleast partially separating the convection air flow to the controller 100from air channel 810 when the heating fan 100 is stationary. The basisfor this step consists in that the air channel 810 and the area of theheating block 300 are warm during operation of the heating fan 100 andthis heat is given off as after-heat when the device is stationary. Thecontroller is to be substantially spared from this after-heat. However,a certain proportion of after-heat serves to correctly switch off theheating fan and is advantageous for temperature control. Accordingly,the guide wall 112 is arranged between the air channel 810 and a frontinner side 211 in the embodiment example. There is a small gap 113between the guide wall 112 and the front inner side 211. The gap 113advantageously serves to prevent vibrations from being transmitted fromthe air channel to the front 210 and deformation in the front 210 due topressing out of the guide wall 112. The guide wall 112 substantiallyfollows a side of the air channel 810. This one side of the air channel810 is extended farther and terminates with a gap 113 relative to theforward front inner side 211.

The heating block 300 is thermally safeguarded by a safety temperaturelimiter 430 and sits on the heating block 300. Further, a fuse 431 isprovided for additional security. The safety temperature limiter 430 hasa lower shut-off temperature than the fuse 431. The safety temperaturelimiter 430 which is configured as PTC element responds first. Aftereliminating a possible error, the safety temperature limiter 430 resetsand the heating fan 100 can be operated again. The fuse 431, which isprovided with a higher shut-off temperature, responds when a temperaturein the heating device exceeds the shut-off temperature of the safetytemperature limiter 430. An additional thermal safeguarding of theheating fan 100 is achieved in this way. The heating block 300 isadvantageously outfitted with a self-regulating heating element,particularly with self-regulating ceramic heating elements 301, whichreduces the heating output with increasing temperature. Therefore, theheating block 300 in the embodiment example is inherently safe.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularembodiments disclosed above may be altered or modified and all suchvariations are considered within the scope and spirit of the invention.Although illustrative embodiments of the invention have been describedin detail herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various changes and modifications can be effectedtherein by one skilled in the art without departing from the scope andspirit of the invention as defined by the appended claims.

1. A heating fan with an inner space having an air channel, comprising:an electric heating body arranged behind a fan in an air flow direction,wherein the fan has a fan wheel of a radial fan with a first suctionside and a second suction side which are separated by a dividing wall,wherein the first suction side is open to a first air inlet openingthrough which a first air flow is sucked in from outside through thefirst suction side during operation, wherein the second suction side isarranged in a fan space of the heating fan, and the second suction sideis pneumatically connected to second air inlet openings, and the fan isarranged in front of the electric heating body so that the first airflow and the second air flow stream through the heating body.
 2. Theheating fan according to claim 1, wherein a guide wall through which thefan space is formed is arranged in the inner space so that at least someof the second air flow is guided to the second suction side.
 3. Theheating fan according to claim 1, wherein the fan space is situatedbetween the second suction side and the second air inlet opening so thatair flows out of an inner space into the second suction side duringoperation of the heating device.
 4. The heating fan according to claim1, wherein the fan has an exhaust opening through which a total air flowis guided to the heating body during operation of the heating fan, andthe heating body is arranged behind the exhaust side in air flowdirection.
 5. The heating fan according to claim 1, wherein the secondair inlet opening is arranged in the rear wall.
 6. The heating fanaccording to claim 1, wherein the first air inlet opening has a largeropening area than the second air inlet opening, wherein the first airinlet opening makes up in particular approximately 55% to 90% of thetotal opening area of first air inlet opening and second air inletopening so that the mass flow of the first air flow is greater than themass flow of the second air flow during operation of the heating fan,and the mass flow through the first opening amounts in particular toapproximately 60% to 80% of the total mass flow.
 7. The heating fanaccording to claim 1, wherein the fan wheel of the fan has first bladeswhich are arranged toward the first suction side, and in that secondblades of the fan are arranged toward the second suction side.
 8. Theheating fan according to claim 1, wherein the first blades and thesecond blades of the fan wheel are separated by a dividing wall.
 9. Theheating fan according to claim 1, wherein the first blades are largerthan the second blades, in particular at least approximately 50% larger.10. The heating fan according to claim 1, wherein the electric heatingbody is a ceramic heating element.